When a single tooth is missing, it may be replaced by a bridge comprising a false tooth anchored to the adjacent teeth which must be healthy, at least in part. Such a denture is fixed. When several teeth are missing, the conventional technique is to fit a metal plate or denture in the patient's mouth, with the plate supporting a set of false teeth. The plate bears on the maxillary cavity or on some of the remaining teeth. However, it is also necessary to anchor it to suitably strong remaining teeth. The anchorage is generally provided by means of clasps placed around healthy teeth. Unfortunately, initially healthy teeth soon decay after clasps have been fitted thereto because of contact with the metal of the clasps and because of the mechanical forces which the plate transmits to the teeth via the clasps. The teeth also tend to work loose under the effect of the lateral forces applied thereto. Further, such clasps are disagreeable to wear and unpleasant in appearance.
In order to remedy these drawbacks, proposals have already been made to replace clasps around healthy teeth by crowning the teeth to provide permanent couplings to which the plate can be removably fixed. The healthy teeth concerned are thus drilled to form a frustoconical post. An artificial crown is then cemented to the post. A part of the crown is made of metal so that a portion of a coupling (generally a male portion) can be soldered or welded thereto prior to the crown being fitted in the mouth. A larger, female portion of the coupling is fixed to the plate, thus constituting an all-metal coupling which is horizontally-releasable. It is thus possible to implant a plate in the patient's mouth without the need for clasps. Once the plate is in place, it is normally completely invisible, thus increasing the patient's mental and functional comfort, (see British patent No. 2 085 303).
This solution also has drawbacks. Firstly it requires a considerable amount of work on the part of the dentist who has to shape the teeth which support the couplings, thereby destroying a considerable quantity of healthy tissue. Secondly, given the forces which are exerted between the plate and the anchor teeth, the anchor couplings need to be replaced at relatively short intervals due to wear of the mechanical connection. By bearing against the tooth-mounted male portions, the denture very quickly causes damage.
Preferred implementations of the present invention mitigate the drawbacks of the second method described above. The invention also provides a mounting which enables the mechanical connection between the plate and the anchor teeth to be replaced extremely rapidly.